Search Results (210)

Entomopathogenic nematodes (EPNs) are among the most promising biocontrol agents; however, their short shelf life constrains commercial application. This study evaluated the effects of storage temperature (6 °C and 25 °C) and sponge substrate moisture content (42%, 48%, and 55%) on the 18-week survival and post-storage virulence of two indigenous EPN species from Gansu Province, China: Heterorhabditis megidis 0627M and Steinernema feltiae 0619HT. A Generalized Linear Mixed Model (GLMM) revealed that storage duration, temperature, moisture content, and species all significantly affected survival of H. megidis 0627M and S. feltiae 0619HT (all p < 0.001). Low-temperature storage (6 °C) reduced mortality odds by 82.4% compared with room temperature (OR = 0.176, 95% CI: 0.117–0.263, p < 0.001). High moisture content (55%) increased mortality odds by 10.1-fold relative to moderate moisture (48%; OR = 10.114, 95% CI: 6.155–16.618, p < 0.001), whereas low moisture (42%) showed no significant difference from 48% (OR = 0.942, p = 0.810). The two species exhibited distinct adaptation strategies: S. feltiae 0619HT achieved the highest survival under low-temperature storage at 48% moisture content (56.48% at week 18), whereas H. megidis 0627M demonstrated a delayed competitive advantage under room-temperature, low-moisture conditions. Virulence assays revealed that low-temperature storage better preserved infectivity under most conditions. Notably, survival and virulence were not always concordant, necessitating their evaluation as complementary metrics. Species-specific storage protocols are proposed, providing a scientific basis for the future development of regionally targeted and cost-effective native EPN formulations, as well as for regionally targeted biocontrol applications. Full article

The tomato leafminer Tuta absoluta (Meyrick) is a devastating invasive pest that threatens tomato production worldwide. Reliance on chemical insecticides raises sustainability concerns, highlighting the need for effective biological alternatives. Combining predators with entomopathogenic nematodes (EPNs) represents a promising strategy, yet their interactions remain poorly characterized. Here, we conducted laboratory bioassays to assess the individual and joint effects of the predatory bug Arma chinensis (Fallou) and four EPN species, Steinernema carpocapsae, S. feltiae, S. riobrave, and Heterorhabditis bacteriophora, against T. absoluta larvae. Under these controlled conditions, H. bacteriophora showed the highest compatibility with A. chinensis, exhibiting the lowest virulence against the predator. Female A. chinensis exhibited strong predation on freely exposed second-instar larvae, but efficiency declined markedly against leaf-mining larvae. Heterorhabditis bacteriophora caused consistently high mortality in second instars regardless of protection. Their combined application resulted in additive mortality with significantly reduced LT₅₀ values. We also observed A. chinensis preying on nematode-infected larvae and occasional infection of the predator under confined conditions. These laboratory findings demonstrate additive effects against T. absoluta, providing preliminary evidence for stage-specific integrated biological control strategies. Full article

Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) is a common pest in poultry farms, causing significant economic damage, spreading easily and quickly. The species is resilient, adaptable, and capable of thriving in a variety of environments, and both larvae and adults can hide in hard-to-reach places; thus, control becomes highly challenging. Moreover, the species has developed resistance to commonly used insecticides, increasing the need to adopt integrated pest management strategies. Hence, this study examined the mortality dynamics of A. diaperinus larvae exposed to the entomopathogenic nematodes (EPNs) Heterorhabditis downesi Stock, Griffin & Burnell 2002 (Rhabditida: Heterorhabditidae) and Steinernema kraussei (Steiner, 1923) (Rhabditida: Steinernematidae) across a range of temperatures, dose rates, and exposure intervals. The patterns of larval mortality closely followed the classical EPN infection timeline: limited mortality during the first hours, a pronounced increase between day 2 and 4, and high cumulative mortality after day 8. Steinernema kraussei produced moderate early mortality, increasing by day 8, across all tested temperatures, reflecting its relatively slower but effective infection progression. In contrast, H. downesi induced higher early mortality at moderate temperatures and stronger dose-dependent responses. Temperature significantly modulated infection in both species, with reduced performance at 35 °C, particularly for H. downesi, although high-dose treatments achieved substantial mortality. The significant temperature × dose × time interactions align with established EPN biology and previous research on both species and, overall, the results confirm that they both possess strong pathogenic potential against A. diaperinus, while their performance characteristics support their suitability as biological control agents for poultry facilities. Full article

The rise in anthelmintic resistance in small ruminants has driven the search for sustainable control alternatives. Among these, entomopathogenic fungi such as Metarhizium robertsii stand out for their potential to reduce the free-living stages of gastrointestinal nematodes (GINs). This study evaluated the field efficacy of M. robertsii (LCM S15) under climatic conditions in the Recôncavo region of Bahia, Brazil. The experiment was conducted between November 2022 and July 2023 in a completely randomized design with four groups (n = 8): aqueous control, oil control, aqueous suspension, and oil formulation of M. robertsii. Egg counts per gram of feces (EPG) and L3 larval recovery were assessed by coproculture and the Baermann technique. Efficacy ranged from 15.23% to 27.34%, with the oil formulation showing higher performance. Haemonchus sp. and Trichostrongylus sp. were the most prevalent genera. These findings suggest the potential of M. robertsii (LCM S15) as a biological control agent under field conditions. Full article

Invasive alien species threaten the security of agricultural and natural ecosystems. Aethina tumida Murray, 1867, threatens bee colony health and apicultural sustainability. However, the entomopathogenic nematode, Steinernema carpocapsae (Weiser, 1955), may be a potential biocontrol agent. Models (MaxEnt and CLIMEX) were used to predict the potential global distribution of both species under climate change. The results indicated that under the current climatic conditions, both models found suitable habitats for A. tumida primarily in South America, southern Africa, and South Asia, whereas S. carpocapsae exhibited a broader global spread. Notably, CLIMEX predicted a more extensive distribution than MaxEnt for both species. The MaxEnt results indicated that North America, Europe, and central Australia are suitable habitats for A. tumida expansion in SSP245 (2050s) and SSP585 (2070s), whereas S. carpocapsae was predicted to expand into Asia, North America, and Africa in SSP126 (2090s), SSP245 (2030s), and SSP585 (2070s). The CLIMEX results indicated that under the A1B and A2 climate scenarios, highly suitable habitats for both species decreased significantly, whereas they are predicted to moderately and marginally increase markedly in the 2100s. The potential distribution of A. tumida will depend on suitable climatic conditions and the presence of host bees. These results provide a scientific basis and support in preventing or controlling A. tumida. Full article

Storage insects consist a continuous global threat to food safety. In this study, the efficacy of the entomopathogenic nematodes (EPNs) Steinernema khuongi and Heterorhabditis downesi was evaluated against larvae of Tribolium castaneum, Tribolium confusum, Tenebrio molitor, and Trogoderma granarium in wheat and maize at six concentrations and two exposure intervals. Both EPNs exhibited higher virulence when applied in wheat than in maize. Generally, larval mortalities were higher under H. downesi treatments vs. S. khuongi, both in commodities and exposures. Notably, the tested EPNs caused high mortalities to T. granarium larvae (range, 88.9–92.2%) and T. castaneum larvae (range, 81.1–94.4%), respectively, at 10,000 IJs/mL in wheat vs. mortality ranges 72.2–77.8% and 74.4–87.8% in maize, respectively. In contrast, T. confusum larvae were tolerant to both EPNs. Tenebrio molitor larvae were tolerant to S. khuongi (<34.0% mortality) whereas susceptible to H. downesi (>83.3% mortality) at 10,000 IJs/mL in wheat and maize. These findings highlight the potential of S. khuongi and H. downesi as beneficial organisms against several stored-product insect pests. Full article

The current model of agricultural development, largely focused on the intensification of production, causes increased pressure on the natural environment and, at the same time, does not guarantee sufficient food supplies in the era of global demographic expansion. In light of current environmental changes and the escalating food shortage, the modern agricultural paradigm must strive to achieve a balance between productivity and the quality of agricultural products produced within an environmentally responsible production system. A promising and sustainable tool for future agriculture is a biorational model of agricultural production based, among other things, on the biological protection of agricultural products. The study aimed to assess the effectiveness of biological control agents containing entomopathogenic nematodes in controlling pests from the class Gastropoda. The tests showed that these preparations inhibited the feeding intensity of the analyzed pests. Among the insecticidal nematodes, the biological product containing S. carpocapsae at doses of 2000 and 4000 LJ/m² demonstrated the highest effectiveness (mass loss: A. distinctus: 0.61 g, 0.58 g; D. reticulatum: 0.60, 0.71 g). The research conducted indicates that preparations containing entomopathogenic nematodes have the potential to reduce damage caused by slugs in crops. Full article

Soybean root rot, primarily caused by Fusarium oxysporum, leads to severe root decay and substantial yield losses in Glycine max. This study screened ten entomopathogenic nematode-associated symbiotic bacteria for antagonistic activity against F. oxysporum. Among them, Xenorhabdus budapestensis XH-4 exhibited the strongest in vitro inhibition, suppressing mycelial growth by more than 73%. Antifungal activity was primarily attributed to extracellular metabolites, as both fermentation broth and cell-free culture supernatant were effective, whereas bacterial cell suspensions showed no significant inhibition. In greenhouse experiments, 40% (v/v) XH-4 reduced the disease index by 75–80%, comparable to the chemical fungicide metalaxyl–hymexazol. Genome mining revealed 20 biosynthetic gene clusters encoding diverse secondary metabolites, including fabclavine, fabclavine pyrrolizixenamide A, and putrebactin/avaroferrin, which likely underpin the strain antifungal efficacy. Additionally, XH-4 enhanced soybean antioxidant capacity and activated the phenylpropanoid pathway, indicating a dual mechanism involving direct antagonism and induced systemic resistance. These findings support the development of XH-4 as an environmentally friendly biofungicide for sustainable management of soybean root rot. Full article

Entomopathogenic nematodes (EPNs) are crucial biocontrol agents, yet optimizing the yield and quality of infective juveniles (IJs) during commercial liquid production remains challenging. This study utilized a central composite rotatable design to optimize liquid culture parameters (ascaroside, dimethyl sulfoxide, medium volume, IJ inocula) for Heterorhabditis bacteriophora H06 and Steinernema carpocapsae All. The results demonstrated that improving aeration (inferred from reduced media volume), combined with ascr#11 regulation, synergistically enhanced IJ yield and quality. Under optimized conditions, yields reached 3.35 × 10⁵ IJs/mL for H. bacteriophora H06 and 2.67 × 10⁵ IJs/mL for S. carpocapsae All. Crucially, the IJs from the high-yield flask exhibited significantly superior infectivity (24–26% single-IJ infection rate) compared to solid-culture controls (13–14%). Targeted metabolomics profiling of sugar, energy and fatty acids of H. bacteriophora H06 revealed upregulated tricarboxylic acid (TCA) cycle intermediates (citrate, pyruvate) and the significant accumulation of stress-protectant trehalose and immune-modulating polyunsaturated fatty acids (eicosapentaenoic acid, arachidonic acid). These findings establish a fermentation strategy that simultaneously enhances IJ yield and biological quality by reducing media volume (used as a proxy for improved aeration) and supplementing ascr#11. Furthermore, the distinct metabolic profile enriched in energy, stress, and immune-modulating metabolites identified in H. bacteriophora provides a plausible explanatory framework for the parallel phenotypic improvements observed across both species. Full article

The use of Steinernema carpocapsae infective juveniles as biological control agents is a long-standing practice, yet the oral impact of their secreted venom proteins on crop pests remains largely unknown. We evaluated the oral toxicity of S. carpocapsae venom proteins against Spodoptera frugiperda using artificial diet assays. Ingestion caused significant dose-dependent toxicity in early-instar larvae, resulting in mortality and a prolonged developmental duration. Carry-over effects were profound; treated pupae were smaller and malformed, with only 19% of larvae fed on 1000 ng g⁻¹ venom protein-supplemented diet reaching adulthood compared to 92% in controls. Surviving adults lived 30% fewer days and laid over 90% fewer morphologically normal eggs. These physiological disruptions coincided with elevated oxidative stress and detoxification enzyme activity, suggesting the venom induces oxidative and detoxification responses, which may be associated with the observed phenotypic alterations. This study provides the first demonstration of the oral toxicity of entomopathogenic nematode venom proteins, positioning them as a promising resource for the discovery of novel insecticidal proteins for sustainable pest management. Full article

Bursaphelenchus rainulfi is a pine-associated, non-pathogenic nematode that serves as a motile comparative species for evaluating nematophagous fungi. We investigated the in vitro biocontrol activity of Purpureocillium takamizusanense strain PMEPF27, originally isolated from insect cadavers in Taiwan, against mixed motile stages of B. rainulfi. Identity of the fungus was confirmed by morphology and ITS/EF-1α sequencing. Nematodes were exposed in liquid suspension to PMEPF27 conidia, with sterile water as the negative control and fluopyram as the positive control. Mortality was monitored over 7 days, and scanning electron microscopy was used to observe fungus–nematode interactions. PMEPF27 caused significantly higher mortality than the water control, reaching ~80% by day 7, and showed surface disruption of nematode cuticles, although no direct spore penetration was observed. These findings expand the nematophagous profile of P. takamizusanense beyond egg and sedentary stages, validate B. rainulfi as a motile comparative species in pine-nematode bioassays, and highlight PMEPF27 as a promising candidate for biocontrol development. Full article

Nematodes in the genus Oscheius (Rhabditidae) have traditionally been regarded as free-living bacteriophagous or necromenic associates of insects. Over the past two decades, however, multiple Oscheius species and isolates have been shown to express facultative pathogenicity toward insects and, in some cases, parasitism of mollusks. This has stimulated interest in Oscheius as a complementary group of biological control agents that may function under conditions limiting classical entomopathogenic nematodes (EPNs) of the genera Steinernema and Heterorhabditis. Here, we synthesize current knowledge on Oscheius taxonomy and diversity, life-history strategies, bacterial associations and virulence mechanisms, evidence for control of insect and mollusk pests, and recent advances in chemo-ecology relevant to host finding. We emphasize that Oscheius represents a continuum of ecological strategies, and we adopt conservative terminology in which “entomopathogenic” is reserved for Oscheius species/isolates that meet operational criteria of insect pathogenicity. Finally, we highlight key barriers to wider implementation—strain variability, bacterial partner instability, non-target and community effects, and production/quality control needs—and propose research priorities for the development of robust, field-reliable Oscheius-based biocontrol. Full article

This study evaluated entomopathogenic nematodes (EPNs) isolated from a cacao agroforestry system in the Peruvian Amazon, focusing on their molecular characterization and efficacy against Spodoptera frugiperda (Lepidoptera: Noctuidae) larvae. Thirteen EPN isolates were obtained from 50 soil samples using the Galleria mellonella baiting technique. Mortality assays revealed significant differences among isolates at 24, 48, and 72 h, with isolates 11N-A4 and 8N-B1 being the most virulent, achieving maximum mortalities of 100% and 96.3% at 72 h, respectively. Median lethal time (LT₅₀) values indicated rapid action of these isolates on G. mellonella larvae, with 33.3 h for 11N-A4 and 32.4 h for 8N-B1. Molecular identification using ITS, D2–D3 (LSU), and COI markers confirmed the isolates as Heterorhabditis sp. (11N-A4) and Heterorhabditis amazonensis (8N-B1). In bioassays with S. frugiperda larvae, both EPNs exhibited dose- and time-dependent mortality. H. amazonensis showed rapid action, reaching 100% mortality at the highest dose (60 IJs/larvae) within 48 h, whereas Heterorhabditis sp. displayed a gradual, sustained increase, attaining 91% mortality at 72 h. Median lethal dose (LD₅₀) and LT₅₀ values reflected the efficiency of both isolates, with Heterorhabditis sp. achieving lower LD₅₀ at later stages and shorter LT₅₀ at low-to-intermediate doses. These findings highlight the potential of Heterorhabditis sp. and H. amazonensis as effective biocontrol agents adapted to local conditions and represent the first report of H. amazonensis in Peru. Further studies under field conditions are required to confirm their suitability for incorporation into integrated pest management strategies in the Peruvian Amazon. Full article

The South American tomato pinworm, Tuta absoluta, is a devastating invasive pest that threatens global tomato production, while entomopathogenic nematodes (EPNs) represent promising biocontrol agents. Because a detailed understanding of the molecular basis of the insect immune response is crucial for uncovering how hosts detect and counteract nematode infection, such knowledge may reveal weaknesses exploitable for improved control strategies. However, the molecular mechanisms governing the immune interaction between this pest and EPNs remain poorly understood This study investigated the biocontrol potential of a native Chinese EPN strain, Heterorhabditis indica CQ7-2, against T. absoluta and delineated the host’s molecular immune responses via a time-course transcriptomic analysis. Bioassays revealed that H. indica CQ7-2 LC₅₀ was 1.35 IJs per larva. Comparative transcriptome profiling of larvae revealed that the EPN infection was associated with transcriptional patterns consistent with immunosuppression. Key genes involved in humoral and cellular immunity were significantly suppressed during the early and middle infection stages. Although a widespread upregulation of immune genes occurred after 18 h post-infection (hpi), it was insufficient to prevent host mortality. These findings demonstrate that the virulence of H. indica CQ7-2 is underpinned by associated with modulation of key immune pathways, leading to an ineffective defense response. This work provides deep insights into the molecular arms race between an invasive pest and a native EPN, supporting CQ7-2 as a promising biocontrol agent and providing a framework for understanding host-EPN interactions. Full article

Berry crops such as strawberry Fragaria × ananassa (Weston), raspberry Rubus idaeus L., blackberry Rubus ulmifolius Schott, 1818, and blueberry Vaccinium myrtillus L. are economically and nutritionally valuable worldwide. However, the intensive use of synthetic pesticides for pest management in these crops has led to ecological imbalance, pest resistance, and negative effects on non-target organisms and human health. The integration of biological control agents into sustainable integrated pest management (IPM) systems represents an alternative. This review compiles and evaluates current advances in the application of baculoviruses (BVs), entomopathogenic fungi (EPFs), nematodes (EPNs), predatory mites (PMs), and parasitoid wasps (PWs) for pest suppression in berry crops. Emphasis was placed on their ecological interactions, host specificity, and compatibility within IPM frameworks. The combined use of micro- and macrobiological control agents effectively reduces key pest populations. However, field efficacy remains influenced by abiotic stressors such as UV radiation, temperature fluctuations, and chemical incompatibility. The integration of native micro- and macrobiological control agents of through conservation biological control (CBC) strategies can enhance sustainability in berry production systems. Future efforts should focus on formulation improvements, adaptive management under field conditions, and synergistic interactions among microbial and arthropod natural enemies. Full article